Temperature time integrator



May 8, 195l J. w. coLg TEMPERATURE TIME INTEGRATOR Filed .June 5, 194e INVENToR JAMES W. @LE

ATTORNEY Patented May 8, 1951 UNITED STATES PATENT OFFICE TEMPERATURE TIME INTEGRATOR- .I ames Webb Cole, Charlottesville, Va., assignor to the United States of America, as represented by the Secretary of the Navy Application June 5, 1946, Serial No. `674,616

7 Claims. 1

The present invention relates to temperaturetime integration.

More specifically, it relates to a process of and means for indicating the probable condition of articles that may deteriorate with time and on exposure to heat.

A particular object is to provide means for estimating the condition of electric cells or batteries.

In one form of the invention, an indicator is stored with the articles to be judged, so as to be subjected to the same aging influences of time and temperature as the articles.

A convenient indicator is one depending on chemical action, as, for example, the progressively spreading change of color of a material when subjected to the influence of a gas or other chemical agent.

While the invention, in its broader aspect, is independent of apparatus, two convenient devices embodying it are disclosed herein for illustrative purposes.

In the accompanying drawings:

Fig. 1 is a sectional diagram of a U-tube indicator.

Fig. 2 is a sectional diagram of a more compact alternative type.

With reference to Fig. 1, an inverted glass U-tube I has an enlarged arm 2, containing a material 3 that will liberate an efllux of any kind, such as gas, Water vapor, or colloidally fine particles of a liquid or solid. Examples of such material Will be given hereinafter.

A retaining plug 4 of any suitable brous material, not appreciably affected by the substances involved, covers the material 3. On top of the plug 4 is a plug 5 of coarsely porous nature, such as a quantity of glass beads or other material not deleterious to the said eiliux. An additional .plug 6, Which` may consist of a Wad of fabric such as Woven glass, for example, is placed over the plug 5. The tube, I is constricted beginning at the portion containing the plug 6 and continues to form the other arm 'I of the tube.

This other, smaller arm 'I of the U-tube, rst has a porous .plug 8 inserted therein near the top. Below this is a filling of a sensitive agent 9, and nally a plug I at the bottom to hold the column 9 in place. The plugs 8 and I0 may be Wads of glass fabric or of glass Wool, for convenience, but any other suitable pervious material, substantially inert to the contents of the U-tube, will serve. The arm 'l is sealed at Il, after filling.

The embodiment of Fig. 2 is essentially similar 2 in nature to that of Fig. 1, but physically is more compact and consequently more rugged.

It comprises a centrally located container I2, having a closed bottom and open top, and which may conveniently be made of glass. It contains a filling I3 of elux-producing material, held in place Iby a plug I4 similar to the plug el and a lling I5 of beads, held in `place by a brous plug I8. An outer transparent container Il is spaced from the inner container I 2.

A sensitive agent IB, in this form, is enclosed in the outer transparent container Il and held in place by a porous plug I9. The outer tube may be drawn together and sealed, as shown at 2 I. A plurality of teats or projections 22 may be provided at the ends of the container I2, to assist in holding it concentrically in place in the outer container I'I.

It should be understood that, if preferred, the contents and functions of the containers I2 and Il may be interchanged, so that the inner tube will house the indicator I8. In such case, it is obvious that the level of filling of the outer container must be low enough, or a clear space left, on one side, to afford a View of the inner indicator.

The efflux-producing material used in either form of apparatus may be of various chemical natures. A preferred one consists of a mixture of solid ammonium chloride and solid barium hydroxide. The mixture slowly evolves ammonia. While certain other oxides or hydroxides also liberate ammonia when in contact with an ammonium salt, this particular mixture is desirable because of the suitably low rate at which the reaction proceeds, commensurate with the rate of aging of the battery cells to be indicated.

Ammonia gas is an eillux suitable for changing colors of many compounds of metals, by forming metal-ammonia compounds, for example:

Indicator Color Change Cupric chloride green-yellow to blue. Nickel chloride -A yellow to blue-violet. Cobalt chlor1de pink to blue-violet. Cobalt bromide T pink-red to blue-violet.

large number of substances. water vapor are as follows:

Some results with Indicator Color Change yellzgv to blue-green,

o.V blue-gre'eriito red-pink. blue to pink.

It may also be mentioned that many amines, such as methyl amine, also produc'e'color'changeswith many metal compounds. y essary, of course, to use anr amine that. is.- suffi ciently volatile to diffuse through. the apparatusI Two possibilities are suggested: 1) an amine of volatility characteristics that are' commensurate with the object of the aging tests; (2) amixture of an amine salt, such as'Y methyl amine hydrochloride, .and a hydroxide such as bariumhydroxide, wouldslowly liberate methylamine.

A still different Vtype ofaction is obtained by employing mercury vapor as-the-eillux, and. pal-- ladous-chloridel as the indicator, whereupon theY colon change. is.- from light 'yellow to black.

Inf order toprovide anfeifectiveindicator, it is clear that the'veiiluxsshouldvbe` substantially fully absorbed? bythe sensitive agent-upon contact, soy .that a relatively sharp vline of demarcation willr appear betweerrthe unaltered remaining column or agent,I and the end portion that has been'A changed-incolor;

Obviously, theextent to which the color changeV progressesis determined -by the; amount of eiiluxA produced and.` by the crossesec'tiona-l" area ofthe sensitiveagent, and, therefore, variations maybe' provided by suitable changes in the relative amounts of the"v respective materials, and in the cross-sectionof the column-.ofsensitive agent.

Tests were made' of a device like that shownl inf'llig.- 1, whereinf'the: indicator was cobalt bromide depositedon granules of. puriedzsilican gel, 18s-20' mesh; andf the-active constituent', that yieldedthe` efux', in this instance: gaseous am# monia, was a mixture of solid ammonium chloar ride'andsolid barium hydroxide;

This` mixture'formed a coluinn1f-56 in diam-l eter and 1.5" long, in the largerediameter armY of: the U tube. Thesmaller arm'was.0:3'bore`, which was occupied by a column ofthe indicator, with suitable porous plugsv of glassV wool' and., glass t beads arranged'as-.shown in Fig. 1 ofthe drawing.V Preliminary tests; made with various lengths vand4 horesl oil the:v connecting tubeI between the' mixture and the' indicator, showed that foranyl'ength ofi" connection even` very` much' greaterV than. any that would reasonably be considered, no diiiculty or inaccuracy' was introduced; as the; eiiiuxiwa's capable of dilusing at a` rate far exceeding-1 its;` necessarily relatively low rate of emanation from the mixture. Y'

The surface. ofdemarcationrbetween the unal tered-indicator and the affected,portiont'hereofY was-1 sensibly a plane normal-tothe axis`- of the: column.-andwasfairly` sharply defined?, with a veryV short zonev of transitioncolorsbetweerrthe originalredand the` naldeep blue.v The exact locationv of theend ofA the: blue` columnY couldV therefore? befmarkedz onf the outside of the tube; asbyl anr ink;mark or a piece of. paper or adhesive tape applied to the tube.

Quantitative results,` obtained bymeasuring the changeiof'positijon: ofthis-l blue coloration, are given below;

It.v wouldbe: nec.-

Time, Days (24 hr.)

The information. thus gained may be applied directly'to'fth'e desired purpose of indicating the condition: of certain.l perishable articles that age more rapidly asV the temperature increases, for example, dry'cells; The accelerated rate of aging of suchlcells, when heated, is well known to battery manufacturers and others who are interested therein, and. it has Abeen found that the rate of evolution of ammonia by the mixture closely` parallels theirate of aging or deterioration'of such dry cells, when subjected. to similar temperatures. I-Iencabyr storing an indicating device according' to the present invention in the same package with thefreshly made cells, and marking the. location of theV plane of demarcation on the indicator, at the time of packaging the cells, it will be known that. if, the said pla-ne has progressed,Y say, one inch` the. conditionoff the cellsis somewhat questionable, while if. it has progressed one. and onehalf inches the cells have deteriorated tov such extent-that they shouldlbe discarded. It is of' course. not. possibleV tov state offhand just what correlationexists.between any make. and size of dry cell'. and the corresponding. rate Vof color,

change, but having once determined. this for. any; given. brand and. size, the information1 may be used withiconfi'dencefor futureV shipments ofthe samekind. oficell.

In use, the freshly made device is. stored withfrom the materialthat'is of such` nature thatit may travel or. diifuse away therefrom to reach therindicator, whether it. be a gas orvapor oraY colloidal liquid or colloidal solid,.such as isco'mE monly calleda mist', fog, Yor smoke. The expression aeriforrneiilux is .used to designatea true gasand/orpvapor.

I' claim:

1. A device for integrating a function oftem- Iperature with respectVV totiine, which consists of a sealedcontainer having a translucid portionpa' dry composition!r including' barium: hydroxide mixed with an ammonium salt within the container, saidf composition evolving ammonia at a rate determined by the total/amount or"y the composition and by the temperature towhich it is subjectedand acolumn'of indicator that changes container, and having only one end exposed` di'- rectly to the atmosphere within said container.,

said indicator being visible through said trans- `lucid portion, and located and exposed to be` af fected progressively from said exposedY endA ofthe color in responseto ammoniaand also withinthe column toward the other by said ammonia, to give a quantitative indication thereof.

2. A time and temperature integrating device consisting of a sealed translucid container having two distinct but communicating parts, one of said `parts containing a dry mixture of ammonium chloride and barium hydroxide, and the other containing a column of a chemical indicator that changes its color upon exposure to ammonia, said column being so conned that the ammonia evolved from the mixture has direct access to only one end thereof.

3. An apparatus for use in determining the condition of material subject to aging by time and heat, which comprises a closed container containing a composition that yields an eiilux, said composition being of such amount and so chosen that the rate of production of said efflux is approximately proportional to the rate at which the said material ages, and a chemical indicator reactive with and progressively accessible to the eiux, and showing by the extent of a resulting change in its appearance the total amount of eiliux said composition has evolved, whereby the appearance of the indicator within the apparatus, when said apparatus has been stored with the material to be judged, will provide an approximate indication of the condition of the said material at any time.

4. An apparatus for use in determining the condition of an article subject to deterioration by age and heat, which comprises an enclosure containing a composition that continuously evolves an efflux at a rate affected by temperature, said composition being so chosen that the said rate is approximately a measure of the aging eiTect of heat on the article, and means in contact with and quantitatively responsive to the eiilux for indicating the total amount that has been evolved at any time, whereby the apparatus, when stored adjacent the article to be judged and thus subjected to the same time and temperature conditions as the said article, will afford an indication of the approximate condition of the said article.

5. An apparatus, comprising a sealed vessel containing a dry composition for evolving ammonia, at a rate that is negligible at temperatures below C. and that increases with temperature, and an indicator within the said vessel and exposed at one end only to the said ammonia, said indicator comprising a column of cupric chloride,

which upon reacting with the ammonia will change from its original color to a deep blue color.

6. A time and temperature integrating device comprising two communicating vessels sealed against the outer atmosphere, the rst vessel containing a dry mixture of barium hydroxide and an ammonium salt, and the second vessel being relatively long compared to its cross sectional area of bore and containing a dry chemical indicator including cupric chloride, formed into a column by said second vessel, whereby one end of said column is relatively nearer the first vessel than the other end of said column, and whereby also said column of indicator will be progressively deepened in color from said nearer end to its remote end as ammonia is progressively evolved by said mixture and absorbed by said indicator, said second vessel being at least in part translucid whereby said indicator color may be seen therethrough.

7. A time and temperature integrating device as dened in claim 6, wherein the indicator comprises cupric chloride deposited on granules of silica gel.

JAMES WEBB COLE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,021,058 Machlett Mar. 126, 1912 1,321,062 Lamb et al Nov. 4, 1919 1,777,353 Davis Oct. 7, 1930 2,046,863 Allphint July 7, 1936 2,111,301 Schroter Mar. 15, 1938 2,174,349 Littlefield Sept. 26, 1939 FOREIGN PATENTS Number Country Date 345,672 Great Britain Mar. 23, 1931 478,140 Great Britain Jan. 10, 1938 OTHER REFERENCES Mellor: Comp Treatise on Inorg. Chem, vol. 15, p. 663, lines 21 to 24, Longmans, Green and Co., 1936. 

